Venus

Venus, the second planet from the Sun, is often referred to as Earth's twin due to its similar size and mass. However, this resemblance is superficial, as Venus boasts a thick and dense atmosphere composed primarily of carbon dioxide, with a cloud layer of sulfuric acid enveloping the planet. The mean surface temperature reaches a staggering 737 K (464 °C; 867 °F), and the atmospheric pressure is ninety-two times greater than that of Earth, creating conditions that turn the lowest atmospheric layer into a supercritical fluid.

Orbiting closer to the Sun than Earth, Venus has a unique relationship with our planet, coming into proximity every 1.6 years. This synodic period allows Venus to be the closest planet to Earth, making it a popular waypoint for interplanetary missions. Despite having no moons, Venus exhibits a slow retrograde rotation, resulting in a day that lasts 116.75 Earth days, which is nearly half of its solar year of 224.7 Earth days.

Venus's internal structure consists of a core, mantle, and crust, with heat escaping through active volcanism rather than plate tectonics. It is believed that Venus may have once harbored liquid water and a habitable environment before a runaway greenhouse effect transformed it into the inhospitable world we see today. Interestingly, conditions at certain altitudes in its atmosphere have been identified as potentially favorable for life, prompting renewed interest in exploration.

Throughout history, Venus has captivated human observers and held significant cultural importance. The planet's phases were first discerned through telescopes, providing crucial evidence that supported the heliocentric model of the solar system. The exploration of Venus began in earnest with Venera 1 in 1961, followed by Mariner 2 in 1962, which returned the first data. The first successful lander, Venera 7, reached the surface in 1970, paving the way for future missions, including the upcoming Venus Life Finder, set to launch in 2026.